Stack draft booster and control device for combustion apparatus



Feb. 5, 1952 s. P. CAMPBELL 2,584,326

STACK DRAFT BOOSTER AND CONTROL DEVICE FOR COMBUSTION APPARATUS 2 SHEETS-SHEET 1 Filed May 4, 1948 6 w/ &

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Feb. 5, 1952 CAMPBELL 2,584,326

S STACK DRAFT BOOSTER AND CONTROL DEVICE FOR COMBUSTION APPARATUS Filed May 4, 1948 2 SHEETS-SHEET 2 @zww Patented Feb. 5, 1952 STACK DRAFT BOOSTER AND CONTROL DEVICE FOR COMBUSTION APPARATUS Shirley P. Campbell, Wichita, Kans., assignor to The ColemanCompany, Inc., Wichita, Kans., a corporation of Kansas Application May 4, 1948, Serial No. 24,940 e'olaims. (01. 110-160) This invention relates to draft control appara- 1 scribed in detail. It is control apparatus which may be employed with chimneys, etc., to increase the draft thereof and to provide means for maintaining a predetermined desired draft. Yet another object is to provide a flue draft control unit which may be employed with combustion chambers and outlets, such as chimneys, stacks, etc., for maintaining a, desired draft for the heating unit, etc. A still further object is to provide in combination with a combustion chamber and a chimney, blower means for ejecting hot gases from the combustion chamber into the chimney, while at the same time providing pressure-responsive regulating means for controlling the intake of air and thus maintaining a predetermined draft for the combustion chamber. Other specific objects and advantages will appear as the specification proceeds.

The invention is illustrated, in a single embodiment, by the accompanying drawing, in which- Figure 1 is a side view in elevation of apparatus embodying my invention, the blower being shown duced casing portion I li at its forward end. The

forward end lfl may be introduced directly into the chimney, stack, etc., or may be connected thereto by another pipe [2. The portion Id may be integrally formed with the casing Ill, or may be formed separately, as shown best in Fig. 3, and connected to the casing H] by screws or other means.

Extending laterally from the casing i9 is an air inlet pipe l3, as shown more clearly in Fig. 3. The pipe l3 may be equipped with any suitable means for regulating the flow of air into casing It and in response tothe pressure within the conduit whereby a selected draft may be maintained.

In the specific illustration given, the pipe 83 is provided with an annular recess Hi in which is rotatably mounted a ring frame 15. A control valve or wafer I6 is supported upon the ring l5 by means of pivot pins i1.' The structure-shown is well known in the art and need not be deusually weighted on one side, and the pivotal arrangement is off-center, as illustrated in Fig. 1. By rotating the ring 15, the wafer or control member l6 can be caused to tilt easily under the influence of slight reduced pressure in the conduit II], or, by rotation to a different position, the member It can be caused to respond only to a greater reduced pressure within the conduit. To facilitate the rotating of the ring l5, handle members I8 are provided.

While I prefer the regulator valve structure just described because of the accuracy with which it can be set for controlling the intake of air, it will be understood that other devices for this purpose may be used.

Mounted alongside the casing IL! is a motor l9 equipped with a drive shaft 20. The shaft 29 is fixed to the impeller 21 of a blower having the scroll casing 22, shown best in Fig. l. The scroll casing is provided with an inlet 23, and the'outlet of the scroll casing communicates with a curved discharge pipe 24, as shown more clearly in Fig. 3. The discharge pipe 24 extends in wardly to about a. central position within casing 10, and the open end of the pipe faces toward the reduced end portion Ills of the casing. The discharge of air by the blower thus provides a Venturi-like passage, and the ejector-effect causes hot gases to'flow from the combustion chamber toward the chimney.

Operation In the operation of the apparatus, the motor I9 is set into operation and the blower discharges air through the curved discharge pipe toward the reduced neck of casing Ili The hot gases from the combustion chamber are thus drawn into the area around the discharge pipe 2d and are forced into the chimney or other outlet.

Variations in the pressure in the conduit it may occur for various reasons. The operation of the combustion chamber may produce more or less gases. The chimney may be more effective under certain climatic conditions than under other conditions in producing a draft. While the operation of the blower may be relatively constant, the ejector effect does not compensate for such variations in pressure and the combustion chamber would be thus subjected to varying draft conditions. By employing the pressure-responsive regulator valve in the intake pipe l3, air is admitted in more or less volume, depending upon the pressure within conduit [9, and serves to maintain the desired draft for the combustion chamber.

By providing the air intake at a point between the ejector and the combustion chamber, the blower is allowed to work effectively without interference to the flow of air therefrom and into the outlet casing Ill while at the same time the regulator is-eifective in the supplyof mixture of hot gases and fresh air so that the combustion chamber itself is constantly under the selected or desired draft.

The structure forms a compact unit which may be placed within existing flue structures, thus making up the deficiency in draft for chimneys, stacks, etc., and providing the desired draft control for the particular heating unit installed.

While in the foregoing specification, I have set forth a specific embodiment of the invention in considerable detail for the purpose of -illustrating the invention, it will be understood that the details of such structure may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In apparatus for drafting hot gases from a combustion chamber, aconduit casing having one end adapted to be connected for communication with the combustion chamber and the other end adapted to be connected to a chimney, said casing having an air intake on one side, a pressurer-esponsive regulator valve controlling the intake opening and-responsive to the pressure of the air passing inwardly through said opening to open as such pressure increases, and a power-driven blower having a discharge pipe extending into said casing between the air intake and the end of the casing adapted to be connected to the chimney and with its open end facing said end of the casing.

2. In apparatus for drafting hot gases from a combustion chamber, a conduit casing having one end adapted to be connected for communication with the combustion chamber and having a reduced forward end adapted to be connected to a chimney, said casing having an air intake on one side, a pressure-responsive regulator valve controlling the intake opening and responsive to the pressure of the air passing inwardly through said opening to open as such pressure increases, and a power-driven blower having a discharge pipe extending into said casing between the air intake 'and the end of the casing adapted to be connected to the chimney and with its open end facing towards said end of the casing.

3. In apparatus for drafting products of combustion from a combustion chamber, a conduit casing having one end adapted to be connected for communication with the combustion chamber and the other end reduced and adapted to be connected for communication with a chimney, said casing having an air intake on one side and adjacent the inlet side of said casing which is adapted to be connected to the combustion chamber, a pressure-responsive valve pivotally supported in said casing for controlling the intake opening and responsive to the pressure of the air passing inwardly through said opening to open as such pressure increases, and a power-driven blower having a discharge pipe extending into said casing between the 'air intake and the end of the casing adapted to be connected to the chimney and with its open end facing said end of the casing.

4. In apparatus for drafting products of combustion from a combustion chain-her, a conduit casing having one end adapted to be connected for communication with the combustion cham- 4 her and its other end reduced in diameter and adapted to be connected for communication with a chimney, said casing having an air intake pipe extending laterally therefrom, a ring member r0- tatably mounted in said air intake pipe, a pressure-responsive disk pivotally mounted oifcenter in said ring for controlling the intake opening and responsive to the pressure of the air passing inwardly through said opening to open as such pressure increases, and a power-driven blower supported upon said casing and having a discharge pipe extending into said casing between the air intake and the end of the casing adapted to be connected to the chimney and with its open end facing said end of the casing.

5. A flue draft control unit, comprising a conduit casing having its forward end reduced in diameter and adapted to be connected for communication with a chimney and having its other end adapted to beconnected for communication with a combustion chamber, a blower supported by said casing and having its intake on the outside of said casing and its discharge on the inside thereof, a curved pipe communicating with the discharge of said blower and extending to a point adjacent and facing the reduced end of said casing, said casing having an air intake to the rear of said blower and adj acent the second mentioned end of said casing, and a pressure-responsive regulator valve mounted-in said casing air-intake opening-for controlling the air flow therethroug-h,

said valve being responsive to the pressure of the air passing inwardly through said opening to open as such pressure increases.

6'. A flue draft control unit, comprising a 'conduit casing having one end adapted for connection with the combustion chamber of a heater unit and having its othe'rend reduced in diameter, a blower unit secured to said casing and having its intake on the outside of said casing and its discharge on the inside thereof, a curved pipe communicating with the discharge end of said blower and extending to a point adjacent and facing the reduced end of said casing, said casing having an air intake to the rear of said blower and adjacent the first-mentioned end of said casing, and apressure-responsive valve supported in said casing to control the intake opening and responsive to the "pressure of the air passing inwardly through said opening to open as such pressure increases, said curved pipe extending into said casing between said air intake and the end of the casing adapted to be connected to the chimney 'and'with its open end facing said latter end of the casing.

SHIRLEY P. CAMPBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

